
<h1><span class="yiyi-st" id="yiyi-12">numpy.vdot</span></h1>
        <blockquote>
        <p>原文：<a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.vdot.html">https://docs.scipy.org/doc/numpy/reference/generated/numpy.vdot.html</a></p>
        <p>译者：<a href="https://github.com/wizardforcel">飞龙</a> <a href="http://usyiyi.cn/">UsyiyiCN</a></p>
        <p>校对：（虚位以待）</p>
        </blockquote>
    
<dl class="function">
<dt id="numpy.vdot"><span class="yiyi-st" id="yiyi-13"> <code class="descclassname">numpy.</code><code class="descname">vdot</code><span class="sig-paren">(</span><em>a</em>, <em>b</em><span class="sig-paren">)</span></span></dt>
<dd><p><span class="yiyi-st" id="yiyi-14">返回两个向量的点积。</span></p>
<p><span class="yiyi-st" id="yiyi-15">vdot（<em class="xref py py-obj">a</em>，<em class="xref py py-obj">b</em>）处理复数与dot（<em class="xref py py-obj">a</em>，<em class="xref py py-obj">b</em>）不同。</span><span class="yiyi-st" id="yiyi-16">如果第一个参数是复数，第一个参数的复共轭用于点积的计算。</span></p>
<p><span class="yiyi-st" id="yiyi-17">请注意，<a class="reference internal" href="#numpy.vdot" title="numpy.vdot"><code class="xref py py-obj docutils literal"><span class="pre">vdot</span></code></a>处理多维数组的方式与<a class="reference internal" href="numpy.dot.html#numpy.dot" title="numpy.dot"><code class="xref py py-obj docutils literal"><span class="pre">dot</span></code></a>不同：<em>不是</em>执行矩阵乘积，而是先将输入参数平铺到1-D向量。</span><span class="yiyi-st" id="yiyi-18">因此，它应该只用于向量。</span></p>
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<tr class="field-odd field"><th class="field-name"><span class="yiyi-st" id="yiyi-19">参数：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-20"><strong>a</strong>：array_like</span></p>
<blockquote>
<div><p><span class="yiyi-st" id="yiyi-21">如果<em class="xref py py-obj">a</em>是复数，则在计算点积之前获取复共轭。</span></p>
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<p><span class="yiyi-st" id="yiyi-22"><strong>b</strong>：array_like</span></p>
<blockquote>
<div><p><span class="yiyi-st" id="yiyi-23">点积的第二个参数。</span></p>
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<tr class="field-even field"><th class="field-name"><span class="yiyi-st" id="yiyi-24">返回：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-25"><strong>输出</strong>：ndarray</span></p>
<blockquote class="last">
<div><p><span class="yiyi-st" id="yiyi-26"><em class="xref py py-obj">a</em>和<em class="xref py py-obj">b</em>的点积。</span><span class="yiyi-st" id="yiyi-27">根据<em class="xref py py-obj">a</em>和<em class="xref py py-obj">b</em>的类型，可以是int，float或复杂值。</span></p>
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<div class="admonition seealso">
<p class="first admonition-title"><span class="yiyi-st" id="yiyi-28">也可以看看</span></p>
<dl class="last docutils">
<dt><span class="yiyi-st" id="yiyi-29"><a class="reference internal" href="numpy.dot.html#numpy.dot" title="numpy.dot"><code class="xref py py-obj docutils literal"><span class="pre">dot</span></code></a></span></dt>
<dd><span class="yiyi-st" id="yiyi-30">返回点积，而不使用第一个参数的复共轭。</span></dd>
</dl>
</div>
<p class="rubric"><span class="yiyi-st" id="yiyi-31">例子</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">a</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="mi">1</span><span class="o">+</span><span class="mi">2</span><span class="n">j</span><span class="p">,</span><span class="mi">3</span><span class="o">+</span><span class="mi">4</span><span class="n">j</span><span class="p">])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">b</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="mi">5</span><span class="o">+</span><span class="mi">6</span><span class="n">j</span><span class="p">,</span><span class="mi">7</span><span class="o">+</span><span class="mi">8</span><span class="n">j</span><span class="p">])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">np</span><span class="o">.</span><span class="n">vdot</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">)</span>
<span class="go">(70-8j)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">np</span><span class="o">.</span><span class="n">vdot</span><span class="p">(</span><span class="n">b</span><span class="p">,</span> <span class="n">a</span><span class="p">)</span>
<span class="go">(70+8j)</span>
</pre></div>
</div>
<p><span class="yiyi-st" id="yiyi-32">请注意，高维数组是扁平的！</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">a</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">4</span><span class="p">],</span> <span class="p">[</span><span class="mi">5</span><span class="p">,</span> <span class="mi">6</span><span class="p">]])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">b</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">array</span><span class="p">([[</span><span class="mi">4</span><span class="p">,</span> <span class="mi">1</span><span class="p">],</span> <span class="p">[</span><span class="mi">2</span><span class="p">,</span> <span class="mi">2</span><span class="p">]])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">np</span><span class="o">.</span><span class="n">vdot</span><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">)</span>
<span class="go">30</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">np</span><span class="o">.</span><span class="n">vdot</span><span class="p">(</span><span class="n">b</span><span class="p">,</span> <span class="n">a</span><span class="p">)</span>
<span class="go">30</span>
<span class="gp">&gt;&gt;&gt; </span><span class="mi">1</span><span class="o">*</span><span class="mi">4</span> <span class="o">+</span> <span class="mi">4</span><span class="o">*</span><span class="mi">1</span> <span class="o">+</span> <span class="mi">5</span><span class="o">*</span><span class="mi">2</span> <span class="o">+</span> <span class="mi">6</span><span class="o">*</span><span class="mi">2</span>
<span class="go">30</span>
</pre></div>
</div>
</dd></dl>
